I've had the same issue. There's a QuickStart wizard that you can use for security only use cases on a vDS (https://docs.vmware.com/en/VMware-NSX-T-Data-Center/3.2/administration/GUID-E9FBE567-D136-41AF-B8D6-...). I've used that successfully. However it build all the profiles and such for me. If I want to do overlay also and build custom profiles, I can't get the vDS port groups to show up.